高温高压下核废料垫层材料在含盐水溶液中膨胀性衰减规律研究

项目名称： 高温高压下核废料垫层材料在含盐水溶液中膨胀性衰减规律研究

项目编号： No.41272318

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 徐永福

作者单位： 上海交通大学

项目金额： 85万元

中文摘要： 核废料的理想垫层材料膨润土中的蒙脱石受到水溶液、核废料放射热和遇水膨胀产生膨胀力的热?水?力学耦合作用，产生离子交换，引起蒙脱石矿物相变，导致膨胀性发生衰减，影响垫层材料的性能。本项目根据矿物表面的分形模型，建立吸附水溶液体积与表面分维的理论关系；根据吸附过程的能量守恒方程，导出吸附水溶液体积与溶质吸力间的理论公式，提出膨胀变形和膨胀压力的计算方法。采用红外光谱傅立叶变换技术和X射线衍射分析蒙脱石相变特征，采用分子吸附法确定矿物表面分维变化规律，采用扫描电镜分析吸附层厚度，验证膨胀变形的计算方法；利用改装的高温高压膨胀变形试验装置进行膨胀变形试验，采用一维动力反应和质量迁移程序预测核废料垫层材料的膨胀性衰减程度，评价膨润土的膨胀性能。本项目既是有关工程地质的基础理论研究，又解决工程实际问题，不仅具有创新的理论意义，也具有保护环境、造福子孙的社会意义和经济价值，研究成果具有广阔的应用前景。

中文关键词： 放射性核废料；深层地质处置；膨润土；分形；膨胀性衰减

英文摘要： Compacted bentonites are often considered as a possible buffer material in high-level deep radioactive waste disposals. After the installation of waste canisters,the engineered clay barriers are subjected to thermohydromechanical action in the form of aqueous solution infiltration from the geological barrier, heat dissipation from the radioactive waste canisters, and stresses generated by clay swelling under almost confined conditions. This could modify the physico-chemical performance of the barrier, mainly on the interface with the steel container and with the geological barrier. The engineered barrier development necessitates thus the study of the physico-chemical stability of its mineral component as a function of time under the conditions of the repository in the long-term. In this project, the absorbed volume of aqueous solution can be expressed using the surface fractal dimension accroding to the fractal model. From the thermodynamic viewpoint, a balance exists between the decrease in free energy of aqueous solution and the increment in the work of vertical overburden pressure, a correlation bewteen the absorbed volume of aqueous solution and the osmotic suction is deduced. Swelling deformation can be calculated from the the absorbed volume of aqueous solution. In the expression of swelling deformation, t

英文关键词： Radioactive nuclear waste；deep geological disposal；bentonite；fractal；swell degrade